Question

Two angles are supplementary. The first angle measures 40°. What's the measurement of the second angle? A. 140° B. 120° C. 50° D. 60°

Answer 1

A. 140 degrees is the answer, because two angles that equal 180 degrees is known as a supplementary angle

Answer 2

Supplementary angles add to 180. If we are given the measure of one of the angles, we can find the other by subtracting the known angles from 180.

40 + x = 180

x = 180 - 40

x = 140

The answer is A.